Under the two-picture agreement, Downey will star in Marvel’s The Avengers 2 and Marvel’s The Avengers 3, Marvel announced Thursday.

Joss Whedon is returning to write and direct the sequel to The Avengers, which was the top grossing film of 2012. Disney and Marvel's first film, starring Downey, Chris Evans, Mark Ruffalo, Chris Hemsworth, Scarlett Johansson and Jeremy Renner, has grossed $1.5 billion worldwide to date.

The sequel, which will feature a combination of returning characters and the introduction of new Marvel faces, is slated to begin production in March 2014 and open in theaters May 1, 2015.

Downey has starred as genius inventor Tony Stark since the first Iron Man film, which opened in theaters in 2008. He went on to reprise his role in Iron Man 2 and Iron Man 3, which opened in theaters earlier this summer, on May 3, 2013. The threequel went on to become the most successful Iron Man film and the fifth-highest grossing film of all time globally, earning $1.2 billion worldwide to date.